#4209 Chart grid render fix

Former-commit-id: 79a0e0cf

plugins/org.jkiss.dbeaver.ui.dashboard/src/org/jkiss/dbeaver/ui/dashboard/control/DashboardItem.java

@@ -218,7 +218,9 @@ public class DashboardItem extends Composite implements DashboardContainer {
     @Override
     public void updateDashboardData(DashboardDataset dataset) {
         UIUtils.asyncExec(() -> {
-            renderer.updateDashboardData(this, lastUpdateTime, dataset);
+            if (renderer != null) {
+                renderer.updateDashboardData(this, lastUpdateTime, dataset);
+            }
         });
         lastUpdateTime = new Date();
     }

plugins/org.jkiss.dbeaver.ui.dashboard/src/org/jkiss/dbeaver/ui/dashboard/histogram/DashboardRendererHistogram.java

@@ -116,7 +116,10 @@ public class DashboardRendererHistogram implements DashboardRenderer {
 
 
         // Set background
-        plot.setBackgroundPaint(AWTUtils.makeAWTColor(composite.getBackground()));
+        plot.setBackgroundPaint(histogramChart.getBackgroundPaint());
+        Color gridColor = AWTUtils.makeAWTColor(UIStyles.getDefaultTextForeground());
+        plot.setDomainGridlinePaint(gridColor);
+        plot.setRangeGridlinePaint(gridColor);
 
         DashboardChartComposite chartComposite = new DashboardChartComposite(container, composite, SWT.NONE, preferredSize);
         chartComposite.setChart(histogramChart);